Design of a PMUT array for Multifrequency Imaging

Abstract

In this paper, a piezoelectric micromachined ultrasound transducer (PMUT) array for multi-frequency imaging is investigated. The PMUTs are thoroughly characterized and a finite element model is created in COMSOL Multiphysics (R) software. First, an axisymmetric model of a single PMUT is constructed that couples the solid mechanics, electrostatics and pressure acoustics interfaces. The model accurately predicts static deformation, resonance frequencies and displacement at resonance. Finally, a full 3D model is created to investigate the origin of an observed resonance mode in the array that does not correspond to any flexural mode of the PMUTs. Acoustic crosstalk through the fluid is identified as the likely cause for this "array mode". Acoustic coupling should therefore be considered carefully in future designs and utilized where possible to achieve improved performance or added functionality such as multi-frequency imaging.